In communities that lack modern sanitation systems, proper infrastructure could help turn human waste into a valuable commodity.

MIT spinoutSanergy has developed a model that impacts the entire “sanitation value chain” (pictured below). Waste is collected, stored, and recycled into useful products -- such as fertilizer -- creating work and renewable resources in Mukuru, a 500,000-person Kenyan slum where people often defecate in pits, and sometimes in the streets.

Here, Sanergy manufactures low-cost, concrete-housed bathrooms called Fresh Life Toilets (pictured above), which are franchised to local microentrepreneurs to run as Fresh Life Operators.

Each toilet comes equipped with two removable, airtight waste cartridges -- one for liquid waste, one for solid waste -- as well as conveniences like a trashcan, a sealed bin for sanitary pads, and a solar lantern.

People can use them on an unlimited basis by purchasing a membership for about $1 a month. Franchisees collect the money and can earn extra from selling hygiene-related products, such as toilet paper and soap.

Sanergy collects and transports the waste to a processing facility, where it’s composted with sawdust and microorganisms -- converting collected waste into organic fertilizer.

That’s then sold to local farmers, who used to rely on more expensive, imported fertilizer.

Each of these toilets costs about $600, which includes construction, waste collection, and business and other support from Sanergy. (Partnerships with financial organizations allow the startup to provide zero-interest loans to vetted operators.)

“We’re removing waste and creating value from that waste,” Sanergy cofounder David Auerbach tells the MIT New Office. “As we do, we necessarily build out a market and that incentivizes everyone in the sanitation value chain to participate.”

Since opening its first toilet for business in 2011, Sanergy has erected 330 toilets -- with about 25 new ones added monthly -- removing roughly 1,800 tons of waste. More than 350 jobs have been created in Mukuru: about 170 franchisees, as well people who construct and service the toilets and provide business support to the operators. The startup recently purchased new tech that expedites the waste-to-fertilizer process, and they also hope to convert the waste into other useful byproducts soon, such as biogas and biochar (a type of charcoal).

About 2.5 billion people around the world lack of access to proper sanitation. Nearly 4 billion people are affected if you consider how waste ends up in waterways used for drinking or leached into soil. Within a few years, Sanergy hopes to spread operations across Kenya, the rest of Africa, and eventually South Asia and East Asia.

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York.
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